A fuel cell is constituted by laminating a large number of unit cells each capable of generating a power. Heretofore, as a vehicle on which a fuel cell system is mounted, a vehicle is known in which a traction motor is driven by power supply from a secondary battery and a fuel cell (e.g., see Japanese Patent Application Laid-Open No. 9-231991). In this publication, it is disclosed that when starting the vehicle, the traction motor is driven by the power supply from the secondary battery only, until power generation of the fuel cell is stabilized. Then, after the power generation of the fuel cell is stabilized, the traction motor is driven using the fuel cell.